WO2023248858A1

WO2023248858A1 - Content generation device and content management device which register information in blockchain using audio data in video file, and control method and program for same

Info

Publication number: WO2023248858A1
Application number: PCT/JP2023/021832
Authority: WO
Inventors: 啓介田中; 尚彦土田; 大優植野; 稔坂井田; 篤史藤田; 圭一朗久保
Original assignee: キヤノン株式会社
Priority date: 2022-06-22
Filing date: 2023-06-13
Publication date: 2023-12-28
Also published as: JP2024001840A

Abstract

[Problem] To provide a content generation device that can reduce the processing load of generating a hash value to be registered in a blockchain in a configuration that uses audio data in a video file. [Solution] An imaging device 102 generates a video file including video data, audio data, and metadata, and generates a hash value from the audio data and metadata. The imaging device 102 transmits the video file and the hash value to a management system 101, which registers the hash value and metadata on the blockchain.

Description

A content generation device, a content management device, and their control method and program that register information on a blockchain using audio data in a video file.

The present invention relates to a content generation device, a content management device, and a control method and program thereof, which register information to a blockchain using audio data in a video file.

In recent years, information dissemination through video distribution sites and audio media has become more active, and we have entered an era where anyone can view and disseminate information. Under these circumstances, video file processing technology has also evolved, making it difficult for viewers to judge the authenticity of information. As a result, problems such as fake news and fraud incidents are becoming more serious. To address these issues, there is an increasing demand for a mechanism that guarantees the authenticity of video files (that is, that they have not been modified or tampered with).

As a mechanism to guarantee the authenticity of video files, the use of blockchain technology, which is widely used in industries including finance, is being considered. Blockchain technology can prevent tampering with digital data in a decentralized manner and at low cost. For example, a management system using blockchain technology registers the hash value of content and metadata accompanying the content on the blockchain to guarantee the authenticity of the content from the time it is generated (for example, Patent Document 1 reference). This makes it possible to obtain content that has not been processed since its creation from this management system, and to publish the obtained content on the Internet, SNS, or the like.

JP2017-204706A

Recently, there has been an increase in the number of cases in which the audio data in the video file is used instead of the video file itself, which has various information registered on the blockchain. On the other hand, a video file has a larger amount of data than other content such as still image files, and generating a hash value for a video file requires a larger processing load than generating a hash value for other content. Therefore, in the above-mentioned usage pattern, there is a need for a mechanism that can reduce the processing load of generating hash values to be registered in the blockchain.

The present invention provides a content generation device, a content management device, and a control method and program thereof that can reduce the processing load of generating hash values to be registered in a blockchain in a configuration that uses audio data in a video file. I will provide a.

In order to solve the above problems, the content generation device of the present invention includes: means for generating a video file including video data, audio data, and metadata; means for generating a hash value from the audio data and the metadata; The present invention is characterized by comprising a transmitting means for transmitting the hash value and the video file to a content management device that registers the hash value and the metadata in a block of a blockchain.

According to the present invention, in a configuration that uses audio data in a video file, it is possible to reduce the processing load of generating a hash value to be registered in a blockchain.

FIG. 2 is a diagram for explaining functions of a management system as a content management device that communicates with an imaging device as a content generation device according to the present embodiment. 2 is a block diagram schematically showing the configuration of the imaging device of FIG. 1. FIG. 2 is a flowchart showing a procedure of data transmission processing executed in the imaging device of FIG. 1. FIG. 2 is a block diagram schematically showing the configuration of the management system of FIG. 1. FIG. 5 is a diagram showing an example of the configuration of the image database shown in FIG. 4. FIG. 2 is a flowchart showing the procedure of blockchain registration processing executed in the management system of FIG. 1. FIG. 5 is a diagram illustrating an example of a block data structure of a blockchain managed by a blockchain management unit in FIG. 4. FIG. 2 is a flowchart showing the procedure of authenticity determination processing executed in the management system of FIG. 1. FIG.

Hereinafter, embodiments of the present invention will be described. However, the embodiments of the present invention are not limited to the following content.

FIG. 1 is a diagram for explaining the functions of a management system 101 as a content management device that communicates with an imaging device 102 as a content generation device according to the present embodiment.

The management system 101 has a function of managing content acquired from an external device such as the imaging device 102 via the Internet or the like. Management system 101 is implemented by one or more computer devices. In this embodiment, a configuration will be described in which the management system 101 further communicates with and utilizes the blockchain peer-to-peer network 104, but the configuration is not limited to this and may be implemented using other networks.

As shown in FIG. 1, when the imaging device 102 shoots a video, it generates a video file composed of video data, audio data, and metadata to be described later. Next, the imaging device 102 generates an audio file composed of audio data and metadata in the video file. Next, the imaging device 102 executes a hash function on the generated audio file to generate a hash value of the audio file. Since audio files do not include video data, the amount of data is overwhelmingly smaller than video files. Therefore, when a hash value is generated from an audio file, the processing load for hash value generation can be reduced compared to when a hash value is generated from a video file. In particular, it is highly desirable to reduce the processing load of hash value generation in devices such as imaging devices that have lower computational performance than personal computers. Note that the metadata includes attribute information of the image data indicating the photographer of the image data, the time of shooting, the shooting location, the model of the imaging device, the setting values at the time of shooting, etc., and the amount of metadata is smaller than that of video data. small.

Furthermore, in this embodiment, the imaging device 102 performs trimming processing on the audio data included in the generated video file, and executes a hash function on the trimmed audio data and metadata. The portion removed from audio data by trimming processing (trimming portion) is, for example, unnecessary information such as silence or noise that continues for a certain period of time. Conditions for determining such a trimmed portion can be set in advance for the imaging device 102 by a photographer or the like. By performing the trimming process on the audio data, the amount of audio data can be made smaller than before the trimming process, and the load on the process of generating hash values can be further reduced.

The imaging device 102 sends the video file, the hash value (audio hash value), and the detailed hash value calculation information to the management system 101 in association with each other (step (1)). The imaging device 102 may also transmit an audio file in step (1). Although audio files do not include video data, they can be widely used as audio content. The authenticity of audio files can be guaranteed by having their hash values registered on the blockchain in the same way as video files.

The hash value calculation detailed information is information that describes the data (in this embodiment, the audio data and metadata included in the audio file) that has been subjected to a hash function among the data included in the video file. Note that the hash function does not have to be executed on all metadata items, but may be executed on some metadata items. When a hash function is executed on some metadata items, the hash value calculation detailed information indicates which metadata item the hash function was executed on. Further, when performing trimming processing on audio data, the hash value calculation detailed information may include information indicating conditions for determining a trimmed portion.

Note that the hash function algorithm to be used may be only the initially set algorithm, or one of a plurality of algorithms such as SHA256 and MD5 may be selected. If a configuration is adopted in which one can be selected from a plurality of algorithms, the algorithm used for hash value calculation is also described in the hash value calculation detailed information. SHA256 is an algorithm that, when hashing audio data, for example, repeatedly processes the data 64 bytes from the beginning until the end of the data to generate a 32-byte (256-bit) hash value. If the process of using the first 64 bytes of audio data for calculations and skipping the next 64 bytes without using them for calculations is repeated for all audio data, the amount of calculations can be halved. The detailed hash value calculation information in this case can be expressed as "Algorithm, SHA256, Read, 64, Skip, 64" using the CSV file format. Note that the format of the hash value calculation detailed information is not limited to the CSV file format. For example, a widely used file format such as a JSON file format may be used for the hash value calculation details information, or a unique file format may be used.

Note that in this embodiment, a configuration will be described in which the imaging device 102 generates a hash value and transmits it to the management system 101, but the configuration is not limited to this. For example, the management system 101 may generate a hash value based on the audio file acquired from the imaging device 102.

When the management system 101 of this embodiment receives the video file, hash value, and detailed hash value calculation information from the imaging device 102, it generates an authenticity guarantee number that is a unique number within the management system 101. The authenticity guarantee number is an identification number for uniquely identifying the video file.

The management system 101 generates transaction data including video file information such as metadata, hash value and hash value calculation details information, and an authenticity guarantee number, and connects the block in which the generated transaction data is written to the blockchain. . Specifically, the management system 101 issues the generated transaction data and broadcasts it to one or more computers (nodes) participating in the blockchain peer-to-peer network 104 (step (2)). As a result, the transaction data is temporarily stored in the transaction pool, and verification is completed when the transaction data is approved by the miner. A block containing the transaction data is then generated, and the generated block is added to the end of the blockchain. As a result, the video file information will be registered on the blockchain.

After connecting the block in which the transaction data is written to the blockchain in step (2), the management system 101 stores (provides) the video file and the authenticity guarantee number in association with each other in the image database 407 of FIG. 4, which will be described later. . Then, the management system 101 transmits a registration completion notification to the imaging device 102 indicating that the process of registering the information of the video file in the blockchain has been completed (step (3)).

The management system 101 then allows the user (for example, the photographer or image provider) to select a video file to be published on the image publishing site 103 from among the multiple video files registered in the image database 407 ( Step (4)). Specifically, the user can access the web page of the management system 101 from the communication device 105a operated by the user, and select a video file to be published on the image publishing site 103 on the web page. can. The management system 101 provides the video file selected by the user and the authenticity guarantee number associated with the selected video file to the image publishing site 103 (step (5)). At the same time, the management system 101 notifies the communication device 105a that the video file selected by the user in step (4) can now be published on the image publication site 103.

The display of the image public site 103 is controlled so that the authenticity guarantee number provided with the video file from the management system 101 is displayed, for example, near the video file on the web page. Note that the display position of the authenticity guarantee number is not limited to this, and the authenticity guarantee number may be displayed in a position where viewers of the image publishing site 103 can recognize that it is the authenticity guarantee number corresponding to the video file. good.

Viewers of the image public site 103 may want to confirm that the video file displayed on the web page of the image public site 103 has not been tampered with since it was taken. In this case, the viewer first obtains (downloads) the video file and the authenticity guarantee number associated with the video file from the image public site 103 using the communication device 105b (step (6)). Specifically, the viewer accesses the web page of the image publishing site 103 from the communication device 105b, selects a video file published on the web page, and instructs to download it. Upon receiving this instruction, the image publishing site 103 transmits the video file selected by the viewer and the authenticity guarantee number associated with the selected video file to the communication device 105b.

When the download is completed in step (6), the communication device 105b (first communication device) transmits the obtained video file and authenticity guarantee number as well as a request to confirm the authenticity of the video file to the management system 101 (step (7) )). In this embodiment, the authenticity confirmation request is made by the viewer using the communication device 105b to attach the video file and authenticity guarantee number obtained from the image publishing site 103 to the input form provided by the management system 101. It will be done. However, the authenticity confirmation request is not limited to the method of this embodiment. For example, the authenticity confirmation request may be made by sending an e-mail with the video file and the authenticity guarantee number attached to the management system 101. good.

Upon receiving the authenticity confirmation request from the communication device 105b, the management system 101 determines the authenticity of the video file that is the subject of the authenticity confirmation request. In this case, the timing for determining authenticity is when the management system 101 receives a request to confirm the authenticity of image data displayed on the image publication site 103 from the communication device 105b of the viewer of the image publication site 103. , but not limited to. For example, the management system 101 may periodically determine authenticity based on the image database 407. The management system 101 displays the authenticity determination result on the web page of the management system 101, or notifies the communication device 105b of the authenticity determination result by email (step (8)).

FIG. 2 is a block diagram schematically showing the configuration of the imaging device 102 in FIG. 1. The imaging device 102 is a camera such as a digital camera or a digital video camera, or an electronic device with a video shooting function, such as a mobile phone with a camera function or a computer with a camera.

Referring to FIG. 2, the imaging device 102 includes an MPU 201, a timing signal generation circuit 202, an image sensor 203, an A/D converter 204, a memory controller 205, a buffer memory 206, a video output unit 207, a recording medium I/F 208, and a recording medium I/F 208. It includes a medium 209, a hash value generation section 210, a communication section 211, an audio processing section 212, and a moving image generation section 213.

The MPU 201 is a microcontroller for controlling the system of the imaging device 102, such as the imaging sequence. The timing signal generation circuit 202 generates timing signals necessary for operating the image sensor 203 and the audio processing unit 212. The image sensor 203 is an image sensor such as a CCD or CMOS that receives reflected light from a subject and converts it into an electrical signal. The A/D converter 204 converts analog video data read from the image sensor 203 into digital video data.

The memory controller 205 controls reading and writing of the memory, refresh operations of the buffer memory 206, and the like. The buffer memory 206 stores video files and the like generated by the video generation unit 213. The video output unit 207 displays video data included in the video file stored in the buffer memory 206 through a monitor (not shown) of the imaging device 102, and outputs audio through a speaker (not shown) of the imaging device 102. Output data. The recording medium I/F 208 is an interface for controlling reading and writing of data to and from the recording medium 209. The recording medium 209 is a memory card, a hard disk, or the like, and stores programs, audio files, video files, and the like.

The hash value generation unit 210 executes a hash function on the audio file composed of the trimmed audio data and the above metadata to generate a hash value of the audio file. Note that the hash value generation unit 210 may generate the hash value by executing a hash function on the audio data instead of the audio file. Furthermore, in the present embodiment, the MPU 201 may generate the hash value instead of the hash value generation unit 210. The communication unit 211 is connected to the Internet and sends and receives data to and from external devices.

The audio processing unit 212 performs audio processing to convert voices and environmental sounds collected by a sound collection unit (not shown) of the imaging device 102 such as a microphone into electrical signals, and generates analog audio data. The generated analog audio data is converted into digital audio data by the A/D converter 204. The audio processing unit 212 can also perform the above-described trimming process on the digital audio data to generate audio data from which the trimmed portion has been removed. The video generation unit 213 generates a video file by synchronizing audio data and video data based on a time code or the like.

FIG. 3 is a flowchart showing the procedure of data transmission processing executed in the imaging device 102 of FIG. 1. The data transmission process in FIG. 3 is realized by the MPU 201 of the imaging device 102 executing a program stored in the recording medium 209 or the like. The data transmission process in FIG. 3 is executed when the imaging device 102 receives a predetermined video shooting start operation, such as the photographer setting the audio file hash value output and pressing the video shooting button on the imaging device 102. . The audio file hash value output setting is a setting for generating a hash value of an audio file composed of audio data and metadata included in a video file.

In FIG. 3, the MPU 201 drives a shutter (not shown) to control the exposure time (step S301). Next, the MPU 201 performs imaging processing in which the image sensor 203 receives reflected light from the subject and converts it into an electrical signal (step S302). Next, the MPU 201 performs image processing such as development and encoding on the data obtained by the imaging process in step S302 (step S303). This generates video data. After that, the process advances to step S305.

In addition, in parallel with step S302, the MPU 201 controls the audio processing unit 212 to perform audio processing to convert the audio and environmental sounds collected by the sound collection unit (microphone, etc.) of the imaging device 102 into electrical signals. (Step S304). The analog audio data generated by this audio processing is converted into digital audio data by the A/D converter 204. Next, the MPU 201 determines whether or not it has received a command to execute trimming processing from the memory controller 205 or the like (step S305). If the MPU 201 determines in step S305 that a command to execute the trimming process has not been received from the memory controller 205 or the like, the process advances to step S307, which will be described later. If the MPU 201 determines in step S305 that a trimming process execution command has been received from the memory controller 205 or the like, the process advances to step S306, which will be described later. Note that in this embodiment, the photographer or the like can set in advance whether or not to perform trimming processing on the imaging device 102, and the MPU 201 determines whether or not to perform trimming processing based on this setting. It is also possible to control the

In step S306, the MPU 201 controls the audio processing unit 212 to perform trimming processing. In the trimming process, the MPU 201 determines whether the digital audio data obtained by conversion by the A/D converter 204 includes a trimmed portion (for example, unnecessary information such as silence or noise that continues for a certain period of time). If it is determined that the digital audio data includes a trimmed portion, the audio processing unit 212 removes the trimmed portion from the digital audio data to generate “trimmed audio data”. Further, when the trimmed audio data is generated, the audio processing unit 212 removes data of the same time code as the trimmed portion of the audio data from the video data to generate the trimmed video data.

Next, the MPU 201 generates metadata (step S307). Metadata includes attribute information of content. The attribute information of the content is, for example, information indicating the photographer, the shooting time, the shooting location, the model of the shooting device, the settings at the time of shooting, the time code of the trimmed portion, and the like. Note that the information included in the metadata is not limited to the information described above, and the metadata may further include any information that can be set by the photographer. For example, if the photographer is photographing a live music event, the metadata may include information regarding the artist name and information regarding the song. Furthermore, if the photographer is distributing audio, etc., the metadata may include the photographer's name, SNS account, etc. Note that the process in step S307 is also performed when it is determined in step S305 that a trimming process execution command has not been received from the memory controller 205 or the like.

Next, the MPU 201 controls the video generation unit 213 to generate a video file (step S308). Specifically, the MPU 201 controls the video generation unit 213 to generate video data by synchronizing audio data and video data using a time code, etc., and generates video data that is composed of the generated video data and the metadata. A video file in MPEG format or the like is generated. Furthermore, the MPU 201 generates an audio file in MP3 format or the like that is composed of the trimmed audio data and the above metadata.

Next, the MPU 201 executes a hash function on the generated audio file to generate a hash value of the audio file (step S309). Next, the MPU 201 transmits the hash value of the audio file generated in step S309 and the video file generated in step S308 to the management system 101 (step S310). Note that the data transmitted in step S310 may be encrypted. Next, the MPU 201 stores the video file generated in step S308 in the recording medium 209 (step S311), and ends this process.

As described above, in this embodiment, when the audio file hash value output setting is performed, when the imaging device 102 shoots a video, not only the video file is recorded on the recording medium 209, but also the hash value of the audio file is recorded. The value and the video file are sent to the management system 101.

FIG. 4 is a block diagram schematically showing the configuration of the management system 101 in FIG. 1. The management system 101 is composed of one or more computers connected to a network.

Referring to FIG. 4, the management system 101 includes a control section 400, a data reception section 401, a data transmission section 402, an authenticity guarantee number generation section 403, and a transaction generation section 404. The management system 101 further includes a block generation unit 405, a blockchain management unit 406, an image database 407, a hash generation unit 408, and a hash comparison unit 409.

The control unit 400 controls the entire management system 101.

The data receiving unit 401 receives various data from an external device. For example, the data receiving unit 401 receives a hash value of an audio file, detailed hash value calculation information, and a video file from the imaging device 102 . Further, the data receiving unit 401 receives the video file whose authenticity is to be determined and the authenticity guarantee number from the communication device 105b operated by the viewer of the image public site 103.

The data transmitter 402 transmits various data to an external device. For example, the data transmission unit 402 transmits a video file selected to be published on the image publication site 103 and its corresponding authenticity guarantee number to a communication device operated by a user (for example, a photographer or an image provider). 105a. Further, the data transmitting unit 402 transmits the authenticity determination result to the communication device 105b operated by the viewer who has requested authenticity confirmation of the video file.

When the authenticity guarantee number generation unit 403 receives the hash value and the video file from the imaging device 102, it generates an authenticity guarantee number that is a unique number within the management system 101.

The transaction generation unit 404 generates transaction data and broadcasts the generated transaction data to one or more computers (nodes) participating in the blockchain peer-to-peer network 104. The transaction data includes a hash value received from the imaging device 102, an authenticity guarantee number generated when the hash value is received and associated with the video file, and metadata included in the video file. Note that the transaction data may also include an audio file.

When the broadcasted transaction data is approved by the miners and its verification is completed, the block generation unit 405 generates a block in which the transaction data is written, and connects the block to the blockchain.

The blockchain management unit 406 manages the blockchain that is also held by one or more computers (nodes) that participate in the blockchain peer-to-peer network 104. The management system 101 and each node are synchronized with each other so that the blockchains held by each node always have the same contents.

In the image database 407, moving image files and authenticity guarantee numbers corresponding to the moving image files are registered. Specifically, as shown in FIG. 5, the image database 407 is composed of a block ID 501, an authenticity guarantee number 502, and a video file name 503, which are linked to each other.

The block ID 501 is set with a block ID (ID number) that is issued in order every time a block in which a video file is written is connected to the blockchain. That is, each block ID set in the block ID 501 corresponds to one hash value registered in the blockchain.

The authenticity guarantee number 502 is set to the authenticity guarantee number corresponding to the video file.

The file name of the video file received by the management system 101 from the imaging device 102 or the like is set in the video file name 503.

Note that the configuration of the image database 407 is not limited to the configuration described above, and the image database 407 may include other items.

Referring again to FIG. 4, when determining authenticity, the hash generation unit 408 extracts audio data and metadata from the video file transmitted from the communication device 105b of the user (viewer) who has requested authenticity confirmation. , generate an audio file, and run a hash function on the generated audio file to generate a hash value.

The hash comparison unit 409 acquires a block (described later) corresponding to the authenticity guarantee number sent from the user who requested authenticity confirmation from the blockchain managed by the blockchain management unit 406. Then, the hash value (audio hash value) written in the obtained block is obtained. The hash comparison unit 409 compares the hash value obtained from the block with the hash value generated by the hash generation unit 408 to determine authenticity. If the hash value obtained from the block and the hash value generated by the hash generation unit 408 are the same, the hash comparison unit 409 determines whether the video file sent by the user who requested authenticity confirmation has been tampered with since its generation. It is determined that there is no (true). On the other hand, if the hash value obtained from the block and the hash value generated by the hash generation unit 408 are different from each other, the hash comparison unit 409 determines that the video file sent by the user who requested authenticity confirmation has been tampered with since its generation. (not true/false).

For example, if a video file distributed from the image publishing site 103 to the communication device 105b has been tampered with, the tampered video file is sent to the management system 101 along with an authenticity confirmation request. If the video file has been tampered with since its creation, the hash generation unit 408 generates a hash value from the hash value generated by executing a hash function on the audio file generated from the video file and the video file before tampering. The hash value is different from the hash value calculated for the audio file. Further, the hash value stored in the blockchain by the management system 101 cannot be changed by anyone. Therefore, when the above-mentioned authenticity confirmation request is made for a video file that has been tampered with, the hash value generated by the hash generation unit 408 for the audio file generated from the video file and the authenticity of the blockchain The hash value stored in the block corresponding to the authenticity guarantee number of the confirmation request does not match.

On the other hand, if the video file has not been edited or tampered with, the audio file that the hash generation unit 408 generates from the video file is also unchanged. Therefore, if the video file has not been edited or tampered with since its creation, the hash value generated by the hash generation unit 408 for the audio file generated from the video file and the blockchain request for authenticity verification. The hash value stored in the block corresponding to the authenticity guarantee number matches.

In this manner, in this embodiment, the hash values of the video file and audio file transmitted from the imaging device 102 are managed by the management system 101 in association with each other. Thereby, audio files and video files corresponding to this hash value can be easily provided. Note that the image database 407 may also include file names of audio files corresponding to video files as items.

FIG. 6 is a flowchart showing the procedure of blockchain registration processing executed in the management system 101 of FIG. 1. The blockchain registration process in FIG. 6 is realized by the control unit 400 executing a program stored in a recording medium included in a computer that constitutes the management system 101. The blockchain registration process in FIG. 6 is executed, for example, when the data transmission process in FIG. 3 is performed by the imaging device 102 and a hash value and a video file are transmitted from the imaging device 102.

In FIG. 6, the control unit 400 receives the hash value of the audio file, the detailed hash value calculation information, and the video file from the imaging device 102 (step S601). If the received data has been encrypted, the control unit 400 performs a decryption process on the received data. After that, the control unit 400 stores video file information such as a hash value, detailed hash value calculation information, and audio data and metadata included in the received video file in a RAM (not shown).

Next, the control unit 400 generates an audio file from the audio data and metadata extracted from the received video file. Next, the control unit 400 applies the hash function to the audio file (executes the hash function on the audio file) and calculates (generates) a hash value (step S602). Next, the control unit 400 determines whether the hash value of the audio file received in step S601 matches the hash value calculated in step S602 (step S603).

As a result of the determination in step S603, if the hash value of the received audio file and the calculated hash value match, the process proceeds to step S604, which will be described later. As a result of the determination in step S603, if the hash value of the received audio file and the calculated hash value do not match, the process advances to step S609. In step S609, the control unit 400 issues an error notification indicating that the information and data received from the imaging device 102 in step S601 cannot be registered in the blockchain. After that, this process ends.

In step S604, the control unit 400 controls the authenticity guarantee number generation unit 403 to generate an authenticity guarantee number for the received video file.

Next, the control unit 400 registers the hash value stored in the RAM in step S601, detailed hash value calculation information, and video file information such as metadata in the blockchain (step S605). Specifically, first, the control unit 400 causes the transaction generation unit 404 to generate transaction data including a hash value, detailed hash value calculation information, and metadata. Next, the control unit 400 uses the transaction generation unit 404 to broadcast the transaction data to one or more computers (nodes) participating in the blockchain peer-to-peer network 104. When the broadcasted transaction data is approved by the miner and its verification is completed, the block generation unit 405 generates a block in which the verified transaction data is written, and connects (registers) the generated block to the blockchain.

Next, the control unit 400 issues a block ID corresponding to the generated block (step S606). Here, the control unit 400 issues a value generated by executing a hash function twice on the block header as the block ID. Note that although the block ID is used to refer to a block, there is no block ID field within the block.

Next, the control unit 400 associates the issued block ID, the video file received in step S601, and the authenticity guarantee number generated in step S604, and registers them in the image database 407 (step S607). The control unit 400 may further generate an audio file from the audio data and metadata included in the video file, and register the audio file in the image database 407 in association with the same authenticity guarantee number as the video file. Next, the control unit 400 transmits a registration completion notification to the imaging device 102 indicating that the process of registering the information of the video file in the blockchain has been completed (step S608). After that, the blockchain registration process ends.

FIG. 7 is a diagram showing an example of the block data structure of the blockchain managed by the blockchain management unit 406 in FIG. 4. As shown in FIG. 7, a blockchain is a database formed by connecting blocks in chronological order like a chain. A block 701 connected to the blockchain includes a hash 702 of the previous block, a nonce 703, and a transaction 704.

The hash 702 of the previous block is the hash value in the block connected to the blockchain one block before the block 701. The nonce 703 is a nonce value used for mining (verification and approval). Transaction 704 is transaction data generated by transaction generation unit 404. The transaction 704 includes information indicating the type of transaction, a hash value of the audio file received from the imaging device 102 (denoted as "audio hash" in FIG. 7), and metadata included in the video file.

According to the embodiment described above, the hash value of the audio file is generated from the audio file composed of audio data and metadata included in the video file, and the hash value of the audio file and the video file are sent to the management system 101. be done. That is, the hash function is executed not on the video file but on the audio file for which the processing load of hash value generation is lower than that for the video file. As a result, in a configuration that uses audio data in a video file, it is possible to reduce the processing load of generating a hash value to be registered in the blockchain.

Furthermore, in the embodiment described above, the imaging device 102 is a device that photographs a subject and generates a video file. Thereby, in the imaging device 102 that photographs a subject and generates a video file, it is possible to reduce the processing load of generating a hash value to be registered in the blockchain.

Note that although the present embodiment describes a configuration in which the imaging device 102 transmits the hash value of the audio file and the video file to the management system 101, the present invention is not limited to this configuration. For example, the imaging device 102 may send the hash value of the audio file and the audio file to the management system 101. The management system 101 performs the above-described blockchain registration process based on the hash value of the received audio file and the audio file, and registers the audio file in the image database 407 in association with the hash value of the audio file registered on the blockchain. do. Thereby, an audio file corresponding to this hash value can be easily provided.

Furthermore, in this embodiment, the imaging device 102 may transmit the hash value of the audio file, the video file, and the audio file to the management system 101. The management system 101 performs the above-described blockchain registration process based on the received hash value of the audio file, video file, and audio file. Through this blockchain registration process, the video file and the audio file are registered in the image database 407 in association with the hash value of the audio file registered in the blockchain. Thereby, an audio file corresponding to this hash value and a video file obtained by adding video data to the audio file can be easily provided.

In this embodiment, a configuration has been described in which the imaging device 102 generates a hash value of an audio file and sends this hash value to the management system 101, but the configuration is not limited to this. For example, the management system 101 may acquire an audio file from the imaging device 102 and perform a hash function on the acquired audio file to generate a hash value of the audio file. Alternatively, the management system 101 acquires a video file from the imaging device 102 and executes a hash function on the audio file composed of audio data and metadata included in the acquired video file to obtain the hash value of the audio file. may be generated. Even in such a configuration, the same effects as in the embodiment described above can be achieved.

Furthermore, in the configuration of this embodiment, the imaging device 102 performs the trimming process on the audio data, but the configuration is not limited to this, and the management system 101 may perform the trimming process on the audio data.

FIG. 8 is a flowchart showing the procedure of the authenticity determination process executed in the management system 101 of FIG. 1. The authenticity determination process in FIG. 8 is realized by the control unit 400 executing a program stored in a recording medium included in a computer that constitutes the management system 101. In the explanation using FIG. 8, when the viewer of the image public site 103 operates the communication device 105b, the communication device 105b sends a request for authenticity confirmation of the video file displayed on the image public site 103 to the management system 101. Authenticity determination processing is executed. However, the start of the authenticity determination process is not limited to this.

In FIG. 8, the control unit 400 receives, through the data receiving unit 401, an authenticity confirmation request from the communication device 105b operated by the viewer (step S801). At the time of this reception, the control unit 400 also receives, from the data receiving unit 401, the video file whose authenticity is to be determined and the authenticity guarantee number corresponding to the video file.

Next, the control unit 400 queries the image database 407 using the authenticity guarantee number received in step S801 as a key, and obtains the block ID corresponding to the authenticity guarantee number (step S802).

Next, the control unit 400 accesses the block corresponding to the obtained block ID in the blockchain and obtains the hash value (audio hash) stored in the block (step S803).

In addition, in parallel with the processing in steps S802 and S803, the control unit 400 causes the hash generation unit 408 to generate a The function is executed (step S804). Thereby, the control unit 400 causes the hash generation unit 408 to generate (obtain) a hash value. Specifically, the block corresponding to the obtained block ID is accessed among the plurality of blocks constituting the blockchain, and the detailed hash value calculation information stored in the block is obtained. In step S804, a hash value is generated with reference to this hash value calculation detailed information.

After completing the processing in steps S802 to S804, the control unit 400 uses the hash comparison unit 409 to compare the audio hash obtained in step S803 with the hash value generated in step S804 (step S805).

The control unit 400 determines whether the two hash values compared in step S805 match (step S806).

As a result of the determination in step S806, if the two hash values match, the control unit 400 determines that the received video file in step S801 is "true" indicating that it has not been tampered with since its creation ( Step S807). After that, the process advances to step S809.

On the other hand, if the two hash values do not match as a result of the determination in step S806, the control unit 400 determines in step S801 that the received video file is "false", indicating that it has been tampered with since its creation. (Step S808). After that, the process advances to step S809.

Next, the control unit 400 controls the block generation unit 405 to register the determination result of step S807 or step S808 in the blockchain (step S809). Specifically, the block generation unit 405 generates a block in which the determination result of step S807 or S808 is written, and connects the generated block to the blockchain.

Next, the control unit 400 controls the data transmitting unit 402 to notify the communication device 105b, which is the source of the authenticity confirmation request, of the determination result (step S810), and ends this process.

The present invention provides a system or device with a program that implements one or more functions of the embodiments described above via a network or a storage medium, and one or more processors in a computer of the system or device reads the program. This can also be achieved by executing a process. The present invention can also be implemented by a circuit (eg, an ASIC) that implements one or more functions.

101 Management system 102 Imaging device 201 MPU
210 Hash value generation unit 211 Communication unit 212 Audio processing unit 213 Video generation unit 400 Control unit 401 Data reception unit 404 Transaction generation unit 405 Block generation unit 406 Block chain management unit 407 Image database

Claims

means for generating a video file including video data, audio data, and metadata;
means for generating a hash value from the audio data and the metadata;
A content generation device comprising: a transmitting means for transmitting the hash value and the video file to a content management device that registers the hash value and the metadata in a block of a blockchain.
The video file is managed in association with the block ID and authenticity guarantee number of the block,
The content generation device according to claim 1, wherein the video file is provided together with the authenticity guarantee number.
The transmitting means further transmits an audio file composed of the audio data and the metadata to the content management device,
2. The content generation device according to claim 1, wherein the audio file is managed by the content management device in association with an authenticity guarantee number common to the video file.
Further comprising means for performing a trimming process to remove silence or noise that lasts for a certain period of time from the audio data,
The content generation device according to claim 1, wherein a hash value is generated from the audio data that has undergone the trimming process and the metadata.
The content generation device according to claim 1, wherein the content generation device is an imaging device that photographs a subject and generates a video file.
means for acquiring a video file and hash value including video data, audio data, and metadata;
means for generating a hash value from the audio data and the metadata;
If the obtained hash value and the generated hash value match, means for executing a process of registering an identifier that uniquely identifies the video file and the hash value in a block of a blockchain;
means for associating an audio file containing the audio data with the identifier and distributing it to another device;
A content management device comprising:
The content management device according to claim 6, further comprising means for managing the video file in association with the block ID and authenticity guarantee number of the block.
The content management device according to claim 7, wherein the identifier is an authenticity guarantee number.
Further comprising means for performing a trimming process to remove silence or noise that lasts for a certain period of time from the audio data,
7. The content management device according to claim 6, wherein a hash value is generated from the audio data that has undergone the trimming process and the metadata.
The content management device according to claim 6, wherein the video file and the hash value are obtained from an imaging device.
generating a video file including video data, audio data, and metadata;
generating a hash value from the audio data and the metadata;
A method for controlling a content generation device, comprising the step of transmitting the hash value and the video file to a content management device that registers the hash value and the metadata in a block of a blockchain.
obtaining a video file including video data, audio data, and metadata and a hash value;
generating a hash value from the audio data and the metadata;
If the obtained hash value and the generated hash value match, registering an identifier that uniquely identifies the video file and the hash value in a block of a blockchain;
a step of associating an audio file containing the audio data with the identifier and distributing it to another device;
A method for controlling a content management device, comprising:
A program that causes a computer to execute a method for controlling a content generation device,
The method for controlling the content generation device includes:
generating a video file including video data, audio data, and metadata;
generating a hash value from the audio data and the metadata;
A program comprising the step of transmitting the hash value and the video file to a content management device that registers the hash value and the metadata in a block of a blockchain.
A program that causes a computer to execute a control method for a content management device,
The method for controlling the content management device includes:
obtaining a video file including video data, audio data, and metadata and a hash value;
generating a hash value from the audio data and the metadata;
If the obtained hash value and the generated hash value match, registering an identifier that uniquely identifies the video file and the hash value in a block of a blockchain;
a step of associating an audio file containing the audio data with the identifier and distributing it to another device;
A program characterized by having.